1. Technical Field
The present invention relates to a D/A conversion circuit, an A/D conversion circuit, an electronic apparatus, and the like.
2. Related Art
In the related art, as an A/D conversion circuit for converting an analog signal into digital data, a successive approximation type A/D conversion circuit has been proposed. The successive approximation type A/D conversion circuit is provided with a comparison circuit, a successive approximation register, and a D/A conversion circuit, and performs A/D conversion by sampling (performing a sample and hold operation for) an input signal and a successive approximation operation to output digital data. As such a successive approximation type A/D conversion circuit in the related art, a technique disclosed in JP-A-8-321779 is known.
In such a successive approximation type A/D conversion circuit, most of the conversion accuracy depends on the accuracy of the D/A conversion circuit, the accuracy of the D/A conversion circuit directly affects the conversion accuracy of the A/D conversion circuit. Thus, in order to enhance the conversion accuracy of the A/D conversion circuit, it is important to realize a D/A conversion circuit of high conversion accuracy somehow or other.
However, in a case where the D/A conversion circuit is realized as a semiconductor IC, device variation occurs due to fluctuation in the manufacturing process or the like, and the conversion accuracy of the D/A conversion circuit is reduced due to the device variation. For example, in a charge redistribution type D/A conversion circuit, if the capacitance ratio accuracy is reduced due to the device variation of a capacitor, the conversion accuracy of the D/A conversion circuit is reduced. On the other hand, for example, if the layout area of the capacitor is enlarged in order to enhance the capacitance ratio accuracy, there arises a problem that the circuit becomes large-scaled.